Heightened Pelvic Floor Muscle Tone and Altered Contractility in Women with Provoked Vestibulodynia

Abstract

Background Pelvic floor muscle (PFM) dysfunctions are reported to be involved in provoked vestibulodynia (PVD). Although heightened PFM tone has been suggested, the relative contribution of active and passive components of tone remains misunderstood. Likewise, alterations in PFM contractility have been scarcely studied. Aims To compare PFM tone, including the relative contribution of its active and passive components, and muscular contractility in women with PVD and asymptomatic controls. Methods Fifty-six asymptomatic women and 56 women with PVD participated in the study. The PVD diagnosis was confirmed by a gynecologist based on a standardized examination. Outcomes PFM function was evaluated using a dynamometric speculum combined with surface electromyography (EMG). PFM general tone was evaluated in static conditions at different vaginal apertures and during repeated dynamic cyclic stretching. The active contribution of tone was characterized using the ratio between EMG in a static position and during stretching and the proportion of women presenting PFM activation during stretching. Contribution of the passive component was evaluated using resting forces, stiffness, and hysteresis in women sustaining a negligible EMG signal during stretching. PFM contractility, such as strength, speed of contraction, coordination, and endurance, also was assessed during voluntary isometric efforts. Results Greater PFM resting forces and stiffness were found in women with PVD compared with controls, indicating an increased general tone. An increased active component also was found in women with PVD because they presented a superior EMG ratio, and a larger proportion of them presented PFM activation during stretching. Higher passive properties also were found in women with PVD. Women with PVD also showed decreased strength, speed of contraction, coordination, and endurance compared with controls. Clinical Implications Findings provide further evidence of the contribution of PFM alterations in the etiology of PVD. These alterations should be assessed to provide patient-centered targeted treatment options. Strengths and Limitations The use of a validated tool investigating PFM alterations constitutes a strength of this study. However, the study design does not allow the determination of the sequence of events in which these muscle alterations occurred—before or after the onset of PVD. Conclusion Findings support the involvement of active and passive components of PFM tone and an altered PFM contractility in women with PVD.

The impact of a familiarization session on the magnitude and stability of active and passive pelvic floor muscle forces measured through intravaginal dynamometry

“…Women may keep their PFMs more relaxed when they are less anxious about a dynamometric protocol. Indeed, Morin et al recorded higher baseline forces at rest and higher stiffness in women with provoked vestibulodynia (PVD) compared to women without vulvar pain, noting that the women with PVD tended to demonstrate more PFM EMG activation during a passive stretch induced by a dynamometer despite attempts to keep their PFMs relaxed. Further, Gentilcore‐Saulnier et al observed that women with PVD had lower PFM tone after a physical therapy program, and the authors suggested that the decrease in tone could be attributed to a decrease in fear or anxiety when stretching was applied to the vaginal tissues.…”

Can maximal voluntary pelvic floor muscle contraction reduce vaginal resting pressure and resting EMG activity?

“…In general, the responsiveness, reliability and validity of vaginal palpation have been questioned and may be one explanation for the different findings [22]. In a recent published study, Morin et al compared 56 women with and 56 without PVD using dynamometer and sEMG, and found greater PFM resting forces and stiffness measured with a dynamometric speculum in the group with PVD [9]. In a former reported 4D ultrasound study they also found that women with PVD had a significantly smaller levator hiatus area, a smaller anorectal angle and a larger levator angle plate at rest compared with controls, suggesting that this may have been caused by an increased PFM tone [23].…”

“…In addition, "vaginal overactivity", lack of pelvic floor muscle strength and "restriction of the vaginal opening" have been hypothesized to be associated with Provoked vestibulodynia (PVD) [3;4]. To date there are few studies assessing these variables in women with PVD compared to controls and the reported findings on hypertonicity of the PFM are contradictory [4][5][6][7][8][9].…”

Chronic Pelvic Pain: Assessment, Evaluation, and Objectivation

“…The role of brain neuroimaging in CPP patients will be better elucidated in the next section (see Section 3 ). Another recent investigation further assessed neurophysiological modifications in a cohort of Provoked Vestibulodynia [ 126 ], as Pelvic Floor Muscle abnormalities were detected and matched with a surface Electromyographic evaluation. Pelvic Floor Muscles of the patients were stiff and more prone to increased resting and activated muscle tone (during stretching) than control subjects; all these abnormalities were documented by surface Electromyographic recording of anomalies.…”